The present invention relates to devices for aiding handicapped persons by extending their reaching and gripping abilities. More particularly, the present invention relates to gripping and reaching devices for use by persons with grip and wrist disabilities in reaching and lifting objects.
Persons suffering with hip, back or lower extremity injury often lack the ability to grasp objects beyond the restricted range of that person's motion. To assist persons with such handicaps, the prior art has provided mechanical reaching devices which operate to extend the reach and improve the ability of the user to grip objects. Reaching devices generally comprise a support to mount the device on the forearm and wrist or hand, and a trigger mechanism connected by a cable to a pair of pivotal gripper jaws. The user pulls the trigger to close the gripper jaws about an object to be lifted and to control the amount of force applied to the object. Once the object is gripped in this manner, the user then moves his or her forearm to lift the object and place it at a desired location. See, for example, U.S. Pat. Nos. 4,374,600 to van Zelm and 3,986,743 to Bjurling et al.
Benefiting from the use of such reaching devices are persons whose handicaps restrict the person's ability to bend or reach for objects, or to readily move toward the objects which the person must lift. Such handicaps are frequently suffered by persons with arthritis or similarly disabling injuries or diseases. These types of conditions result in a weakening of the user's hand or wrist, thus reducing the person's ability to grasp and lift objects of even moderate weight.
One problem with prior art reaching devices is that the force applied by the gripper jaws to the object to be lifted is dependent upon the strength of the user's grip in operating the trigger mechanism of the device. Unless the user has retained sufficient strength in the wrist and hand, or the object to be lifted is light, it is often difficult of the user to exert sufficient grasping force on the trigger mechanism to hold the object so that it can be lifted and carried.
In order to increase the reach of the user, an extension arm is provided in prior art reacher devices between the gripping jaws and the structure which mounts the device of the forearm and wrist of the user. When an object is picked up by the gripper jaws at one end of the extension arm, a moment in the form of a bending force is produced at the opposite end thereof in the area of the hand and wrist. Another problem with prior art reaching devices of the type described above is that this bending force at the hand and wrist of the user is often substantially greater than the weight of the object to be lifted. The user must therefore not only counteract the bending force produced by the mass of the object with his or her wrist, hand and fingers, but also operate the trigger mechanism at the same time to control the amount of gripping force applied to the object being lifted.
A still further problem with reacher devices of the prior art is that they have been designed with little or no regard for the balance of the device while it is being positioned to grasp an object or while it is carrying an object. As a result, such devices lack stability under load and impart a rotational force tending to cause pronation or supination of the forearm which must be overcome by the user.